UPDATE: AWPA Revises Standards for Treated Wood Usage

The American Wood Protection Associaton (AWPA) recently unveiled upcoming standardization changes for treated wood use. The standards, which will take effect upon their release in May or June, recommend that Ground Contact Treated Lumber be used instead of Above-Ground Treated Lumber in the following above-ground situations:

  • “When there is reasonable expectation that soil, vegetation, leaf litter or other debris may build up and remain in contact with the component.
  • When the construction itself, other structures or anticipated vegetation growth will not allow air to circulate underneath the construction and between decking boards.
  • When components are installed less than 6″ above ground
  • When components are in direct contact with non-durable untreated wood, or any other construction with any evidence of decay.
  • When components are wetted on a frequent or recurrent basis (e.g. on a freshwater floating dock or by a watering system).
  • When components are used in tropical climates.
  • The wood is difficult to maintain, repair or replace and critical to the performance and safety of the entire system.”

These rule changes “took several above ground applications and put them into a ground contact use category,” said Colin McCown, AWPA executive vice president. “This spring, we received new proposals that would create a new use category for severe exposure or critical use above ground applications which seek to offset but not completely undo the changes from the fall 2015 cycle.” Those proposals will be initially considered and could be revised by AWPA’s Technical Committees at a meeting on May 4. If approved at the meeting and in subsequent committee ballots, these changes could take effect as early as the fall of 2016.

Information from manufacturers on the impact of the new rule is conflicting. Several manufacturers have released statements on their websites clarifying their understanding and stance on the upcoming standardization changes.

- Sponsor -

On its website (www.treatedwood.com), Viance, manufacturer of Ecolife Stabilized Weather-Resistant Wood, states: “The proposed changes to the AWPA-UCS above ground standard require the use of wood treated to ground contact (UC4A) retention levels for deck and joist and support beam applications in which the components are critical to the performance and safety of the entire structure and are considered difficult to replace. Recognizing that determining a level of difficulty is subjective and can vary greatly depending on the experience/abilities of any deck builder, the use of above ground retentions for these applications will continue to meet the IBC and IRC building codes.”

In contrast, Wolmanized Outdoor Wood’s website (www.wolmanizedwood.com) states: “Remember that joists and beams for decks and docks fit both of these final criteria [difficult to maintain, repair and replace and critical to the performance and safety of the entire system] and therefore require ground contact treatment.” The site also states: “The International Building Code (IRC) requires treated wood to comply with AWPA standards.”

Koppers Performance Chemicals, manufacturer of MicroPro and NatureWood preserved wood products, states on its website, (http://koppersperformancechemicals.com/) “Ground contact wood should be used …When treated wood is used in an above ground application where the treated wood component would be considered difficult to maintain, repair or replace and that component is critical to the performance and safety of the structure. This standard change will affect joists and beams used in above ground decks.”

What Does this Mean for Dealers?
McCown at AWPA said that regardless of any manufacturer’s interpretation of the standards, a dealer needs to be aware that first and foremost the codes need to be followed at the discretion of the end-user. Whether that’s an architect, a builder or a homeowner, the end-users will be ultimately responsible for interpreting the standards.

“It’s a voluntary standard,” he said. “The end-user has to make the decision to use category 3B or category 4A. The dealer is at the mercy of whoever is making that decision.”

McCown suggests that dealers stock products based on their own market needs and requests.

“If a builder looks at that this new standard and says, ‘holy cow, then that’s everything on a deck,’ then they’ll want everything ground contact. Another builder may not do that. They may look at it and say, ‘this deck is two feet off the ground, it doesn’t need ground contact.’”

Ultimately, McCown said, dealers should “look at their own market and understand which applications apply to their area.”

This story has been updated to include comments from Koppers Performance Chemicals.

Stay Updated

Get our email newsletter with LBM industry trends, data, new products, and best practices.